by Kelly Kennedy, USA TODAY

by Kelly Kennedy, USA TODAY

WASHINGTON - Americans have until March 31 to sign up for health insurance or face a penalty when they file their 2014 taxes next April.

Millions of uninsured people qualify for subsidies to pay for their insurance, but there are still - even after months of advertising, community meetings, door-to-door information sessions and even speeches by the president - many who don't know about the exchanges, don't know they're eligible for financial help, or who don't know the Affordable Care Act still stands. Others simply haven't gotten around to enrolling yet.

"I think that, unfortunately as humans, most of us are procrastinators," said Ceci Connolly, managing director of PWC's Health Research Institute.

Some groups, she said, are holding back a little longer than others.

"More than likely, we're going to see more individuals who perhaps do not speak English as their primary language," Connolly said. "There's a belief that young people tend to wait until the last minute."

Healthier people may make up a big part of the final rush of people signing up, she said. People with health issues, Connolly said, were more likely to buy insurance early, but "there's probably a larger group of healthier individuals who are still out there."

Another impediment, said Katherine Hempstead, senior program officer at the Robert Wood Johnson Foundation, is that many people still don't know if they're eligible for financial help to buy insurance. "People tend to under-predict their own eligibility; they don't know how much help they can get," she said.

A recent Urban Institute survey found that about half of the uninsured have at least visited the exchange websites, but that one out of four of the uninsured hadn't heard of the exchanges at all.

Here's what you need to know to enroll:

1. Start now

While state and federal websites are, for the most part, operating properly, there could be wait times as a throng of people decide to sign up in the last week of March. While enrolling takes an average of 35 to 40 minutes, some people will need more time to enroll if they have complex family situations or aren't familiar with basic insurance terms.

"Plan that it's going to take a little while, and it might take more than one visit," Connolly said.

2. Start at www.HealthCare.gov

Even those who live in states with state-based health exchanges can start at the federal site to get to their state sites. The state and federal exchanges are simply websites that tell people if they are eligible for subsidies, and then allow consumers to compare private health insurance plans - including from Blue Cross/Blue Shield, Aetna and UnitedHealth - by benefits and prices.

There is no "Obamacare" plan. All of the plans are private.

Often, people call and say, "'I want insurance, but I don't want an Obamacare plan,'" said John Arensmeyer, CEO of Small Business Majority, a nonprofit group helping small businesses.

They don't understand, he said, there is no such plan and people have more options to choose from because more insurers, including new co-ops, may now participate without trying to break into a market with an insurance stronghold.

Still, those who are not eligible for subsidies and who don't want to participate in an exchange may buy their insurance directly from an insurer. Because of the law, people with pre-existing conditions may no longer be precluded or charged more for their insurance.

3. How much will it cost?

According to a recent study by PWC, premiums for exchange plans cost the same or less than employer-sponsored plans, and that's before a subsidy.

"Our projection has been that 86% of the newly enrolled will be eligible for subsidies," Connolly said. That includes middle-class families, she said.

A family of four with a household income of less than $95,400 qualifies for a subsidy, as does a single person who makes less than $46,680. In states that have not expanded Medicaid, such as Virginia, Indiana and North Carolina, families with incomes lower than $23,850 may not be eligible for subsidies.

Hempstead said Consumer Reports has a good tool that allows people to check their eligibility without having to fill out all of their basic information first. The Affordable Care Act was written with the assumption that all states would expand Medicaid, but the Supreme Court struck down that portion of the law in 2012. So, those who do make less than 100% of the poverty level in those states will not receive subsidies.

4. What do I need to get started?

You will need income information for you and your family members, as well as Social Security numbers and ages. If you need to see a specialist or go to a specific hospital, you should know which plans cover those providers, which could mean calling the providers and asking.

That starts with understanding how insurance works. For example, a premium is the monthly payment for insurance, while a co-pay is the amount paid for each doctor visit. Studies have shown that many insurance customers still don't understand these terms.

People who are generally healthy might chose a low-premium, high-deductible plan because they don't expect to go to the doctor often or to spend any time in the hospital. Those with chronic issues, such as diabetes or heart disease, might chose a plan with a higher premium to avoid high out-of-pocket costs.

All of those elements are explained at the state and federal websites, but most insurers also have education resources, as does the Kaiser Family Foundation and Families USA.

5. And if I don't?

After March 31, you will not be able to enroll in any health insurance plan - through the exchanges or through the insurers - unless you have a big life change, such as a new job or adding a member to your family.

"The mandate is a reason to enroll, but it's a missed opportunity for insurance, too," Hempstead said.

At tax time next year, those who did not buy health insurance in 2014 will pay either 1% of their yearly household income or $95 per person for the year - whichever amount is higher.

In 2015, the fine increases to 2% of your income or $325 per person. The penalty continues to increase after that. People who have insurance for nine months or more do not have to pay a penalty. Remember, to have coverage beginning April 1, you must choose a plan by March 15.